Stereoscopic endoscopes are known in the prior art. However, they are very large and bulky and hard to use. Also, they include complicated optics which make them very expensive. Because of their size they can create great discomfort to the patient.
In spite of these difficulties, a small diameter stereoscopic endoscope would be desirable because it would give the doctor a three-dimensional view of the operative site. Such a three-dimensional view will greatly enhance the physician's ability to evaluate conditions at the operative site and to successfully manipulate operative devices at the site to complete the desired operative procedure.
Examples of stereoscopic endoscopes are as follows:
Tasaki et al., U.S. Pat. No. 3,520,587, discloses a stereoscopic endoscope having two flexible fiber optic systems with objective lens systems being located at the distal end of each for focusing an image of the site to be inspected. An ocular is located at the proximal end of each fiber bundle for viewing the transmitted images. A visual perception in three-dimension is thereby created. This device is intended to provide a stereoscopic endoscope of limited diameter, but because of the use of light fibers for both transmitting and receiving light and the requirement for relatively sophisticated electronics, the device is still larger than desired and quite costly. PA1 Miyazaki, U.S. Pat. No. 4,926,257, discloses a stereoscopic endoscope comprising a single solid-state image sensor and an optical image system. Stereoscopic imaging is made possible by shifting the solid-state image sensor back and forth between the two optical imaging systems. A prism system is provided in which images are sequentially transmitted to provide the three-dimensional image for viewing. PA1 Jones, Jr. et al., U.S. Pat. No. 4,924,853, also discloses a stereoscopic endoscope using a single imaging lens whereby the image is split by a split beam prism, which images are converted to electrical signals and displayed on a television screen. The images are transmitted from the lens by means of coherent light transmitting elements. This device also provides for the alternate transmission of images to provide a three-dimensional image for viewing. PA1 Yajima et al., U.S. Pat. No. 4,862,873, discloses a stereoscopic endoscope comprising a pair of optical guides which are capable of conducting and illuminating light to be reflected on the site to be observed. While one optical guide conducts the illuminating light, the other optical guide conducts the light from the object being observed. The optical guides can be switched from one function to the other, thereby creating a stereoscopic image. PA1 Tsujiuchi et al., U.S. Pat. No. 4,895,431, discloses a stereoscopic endoscope in which a first endoscope image is taken at one position while a second endoscopic image is taken from a second position. The endoscopic images are partially overlapped with means for detecting the relationship between the first and second images, thereby providing a three-dimensional image.
Each of the devices described above, is complex and therefor expensive. Also, none of them provide an endoscope in which two CCDs are in transverse side-by-side relationship within the endoscope, thereby adding to their complexity and/or size.